Accelerator pedal with braking action

ABSTRACT

An accelerator pedal unit ( 10 ) for a vehicle whereby an accelerator pedal ( 11 ) is moveable from a rest or first position ( 15 ) through an idle position ( 17 ) to a second position ( 16 ) and wherein vehicle braking is caused to occur when the accelerator pedal ( 11 ) moves in the range between the idle position ( 17 ) and the first position ( 15 ) and the vehicle is caused to accelerate when the accelerator pedal ( 11 ) moves between the idle position ( 17 ) and second position ( 16 ).

RELATED APPLICATIONS

This invention is a National Phase in the United States of theInternational Application PCT/AU/01/00582 filed May 18, 2001, and claimsthe benefit of Australian Application No. 35403/00 filed May 19, 2000 inAustralia.

The present invention relates to an arrangement which allows anaccelerator pedal of a vehicle also to influence the braking action ofthe same vehicle and, more particularly, to such an arrangementparticularly suited, although not exclusively, to passenger vehiclesdriven by internal combustion engines.

BACKGROUND

In the vast majority of vehicles on the road today a driver expects tohave one foot pedal devoted to causing the vehicle to be urged toincrease in speed or accelerate (the accelerator pedal) and an entirelyseparate pedal devoted to causing braking or a positive decrease inspeed when pressed (the brake pedal).

Traditionally drivers are taught to use the same foot to operate bothpedals. Hence, when a driver of such a vehicle wishes to brake thevehicle it is necessary for the driver to physically lift his or herfoot from the accelerator pedal, move it over to the location of thebrake pedal and then move his or her foot down on the brake pedal. Thephysical movement of the foot from one pedal to another firstly takestime and secondly is an imprecise operation. For example, a driver,particularly an inexperienced driver or an elderly driver, can initiallymisplace his or her foot relative to the brake pedal. It is not unknownfor a driver, in the course of transferring a foot from the acceleratorpedal to the brake pedal, to move his or her foot beneath the brakepedal instead of over the top of it thereby, as a minimum, leading to anincrease in the time taken to place the foot correctly on the brakepedal and initiate braking of the vehicle and, in the worse case,contributing to an accident where braking is simply not initiated intime as a result of the foot placement error causing initiation ofbraking action of the vehicle to take far too long.

It is an object of the present invention to overcome or ameliorate oneor more of the abovementioned disadvantages or to at least provide auseful alternative.

BRIEF DESCRIPTION OF INVENTION

Accordingly, in one broad form of the invention there is provided anaccelerator pedal unit for a vehicle comprising an accelerator pedaloperatively connected to a vehicle urging means; said accelerator pedalarranged to operate over a predetermined pedal travel which spans from afirst position to an idle position through to a second position; saidpedal also operatively connected to vehicle braking means, whereby saidvehicle via said urging means is caused to progressively increasemagnitude of urging force applied to said vehicle as said acceleratorpedal moves from said idle position to said second position; and wherebysaid vehicle via said braking means is caused to progressively increasemagnitude of braking force applied to said vehicle as said acceleratorpedal moves from said idle position to said first position; saidaccelerator pedal biased in use towards said first position.

Preferably when said pedal is at said idle position said positive urgingforce is approximately 0 and said braking force is approximately 10% ofmaximum braking force.

Preferably when said accelerator pedal is at said first position saidurging force is approximately 0 and said braking force is approximately60% of maximum braking force.

Preferably said vehicle further includes a brake pedal which isphysically moved by said braking means to a position which correspondswith braking force applied by said accelerator pedal unit at any giventime.

Preferably the brake lights of said vehicle are operated when saidbraking means is actuated.

Preferably said pedal is at said idle position, said positive urgingforce is approximately zero and said braking force is approximately zeropercent of maximum braking force

Preferably a mechanical detent arrangement is incorporated in said pedalso as to indicate by mechanical resistance when said pedal is at saididle position.

Preferably said pedal remains at said idle position over a predeterminedangular range of movement.

Preferably said predetermined angular range of movement is approximately5°.

BRIEF DESCRIPTION OF DRAWINGS

One embodiment of the present invention will now be described withreference to the accompanying drawings wherein:

FIG. 1 is a side section, diagrammatic view of an accelerator pedalarrangement incorporating the arrangement of the present invention,

FIG. 2A illustrates graphically the prior art behaviour of a typicalaccelerator pedal arrangement,

FIG. 2B illustrates graphically the behaviour of the accelerator pedalof FIG. 1 according to a first embodiment of the invention,

FIG. 3 illustrates graphically the behaviour of the accelerator pedal ofFIG. 1 incorporating braking action according to a first embodiment ofthe invention, and

FIG. 4 is a block diagram illustrating modifications which can beincorporated into an existing accelerator arrangement of a vehicle inorder to convert it to the operation of the first embodiment.

FIG. 5 is a diagram of accelerator pedal behaviour in accordance with afurther embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

First Embodiment

With reference to FIG. 1 there is illustrated in side section view anaccelerator pedal unit 10 according to a first preferred embodiment ofthe invention.

The unit comprises an accelerator pedal 11 pivotable about pivot 12relative to vehicle floor 13. The accelerator pedal 11 can be pressed bythe foot 14 of a driver (not shown) so as to move through an angulardistance alpha from its rest or first position 15 through to secondposition 16.

In passing from first position 15 to second position 16 the acceleratorpedal 11 passes through an idle position 17 which, in this instance, isat beta relative to vehicle floor 13. As shown in FIG. 1 first position15 of accelerator pedal 11 is the illustrated position at which pedal 11is at alpha degrees with respect to vehicle floor 13.

In this instance accelerator pedal 11 communicates its angular positionwith respect to vehicle floor 13 to an engine urging means which, inthis instance, includes a carburetor 18 via throttle wire 19.

In prior art arrangements carburetor 18 is arranged to make availableincreasing amounts of fuel to the vehicle internal combustion engine thefurther accelerator pedal 11 moves from first position 15 to secondposition 16.

This behaviour of the throttle cable (and carburetor fuel availability)is illustrated graphically In FIG. 2A

In the arrangement illustrated in FIG. 1 according to a first embodimentof the invention the behaviour of the accelerator pedal 11, throttlewire 19 and carburetor 18 combination is varied from the prior art aswill now be described:

With reference to FIG. 2B the throttle wire 19 and carburetor 18 andtheir linkage is adjusted so that movement of throttle wire 19 such asto influence fuel availability via carburetor 18 commences only afteraccelerator pedal 11 reaches idle position 17 and thence continues tolinearly increase until reaching second position 16 as illustrated inFIG. 2B.

In addition, brake urging means in the form of brake vacuum valvecontroller 20 is operatively connected to throttle wire 19 and thenceinterconnected to the vehicle main braking system such that asaccelerator pedal 11 is moved from first position 15 through to idleposition 17 braking force exerted by the vehicle's braking system on thevehicle is varied, in this instance, from 60% of maximum vehicle brakingforce at first position 15 through to 10% of maximum vehicle brakingforce at idle position 17. As accelerator pedal 11 passes through idleposition 17 (at angle beta with respect to vehicle floor 13) brakingforce is rapidly reduced from 10% to 0% as illustrated in FIG. 3 therebyallowing usual vehicle acceleration in the manner illustrated in FIG. 2Bas accelerator pedal 11 moves from angle beta with respect to floor 13through to alpha degrees with respect to first position 15.

The reverse behaviour in terms of engine acceleration and vehiclebraking occurs as accelerator pedal 11 moves from second position 16back to idle position 17 and on to first position 15.

Accelerator pedal 11 is supported and biased (by means not shown) insuch a way that its normal position, uninfluenced by foot 14 is firstposition 15 as illustrated in FIG. 1. Pressing downwardly on pedal 11 bymeans of foot 14 causes pedal 11 to move through idle position 17 and onto second position 16. Conversely, removal of foot 14 from acceleratorpedal 11 causes the pedal to move in a direction from second position 16through idle position 17 and on to first position 15 which is its restposition.

With reference to FIG. 4 the operation of brake vacuum valve controller20 now be described in more detail.

Brake vacuum valve controller 20 comprises, in this instance, a ventedvacuum valve 21 controlled by the position of and operatively connectedto throttle wire 19.

The vented vacuum valve 21 utilises vacuum from engine manifold 22 tomove vehicle brake pedal 23 (illustrated in FIG. 4) to change positionin response to movement of throttle wire 19 over a predetermined rangeof movement and thereby to influence vehicle braking force over apredetermined range of movement of vehicle brake pedal 23, as would beachieved by the driver (not shown) operating vehicle brake pedal 23 inthe usual manner.

In this instance the predetermined range of movement of throttle wire 19is the movement which corresponds to movement of accelerator pedal 11between first position 15 and idle position 17 and which corresponds, inthis instance, to a vehicle braking force varying correspondinglybetween 60% of maximum vehicle braking force and 10% of maximum vehiclebraking force as illustrated in FIG. 3.

More specifically, in this instance, the brake vacuum valve controller20 further includes a vacuum cylinder 24 installed and connected tobrake pedal arm 25 as illustrated in FIG. 4 via pulley 26 and brake wire27. In addition a solenoid valve 28 controls the supply of vacuum viavacuum tube 29 from manifold 22 to prevent operation of brake vacuumvalve controller 20 in specified circumstances.

As previously described the accelerator pedal unit 10 of the firstembodiment of the present invention requires adjustment of the linkageof throttle wire 19 between carburetor 18 and accelerator pedal 11 suchthat, in this instance, there is about 20 mm of play in the throttlewire movement before the engine throttle/carburetor is activated tocause positive urging of the vehicle. This “play” corresponds tomovement of accelerator pedal 11 from its rest or first position 15through to idle position 17 as illustrated in FIG. 1. Over this range ofmovement the accelerator pedal 11, according to the first embodiment ofthe present invention, causes no urging of the vehicle to increase inspeed but, rather, causes a positive braking action to be exerted bymeans of operation of brake pedal 23 by way of brake vacuum valvecontroller 20 as described above.

In use a driver (not shown) will enter the vehicle and start its enginethereby causing solenoid valve 28 to open allowing vacuum to pass frommanifold 22 through vented vacuum valve 21 to vacuum cylinder 24 wherebypulley 26 and brake wire 27 are caused to move so as to move brake pedalarm 25 to a position which exerts vehicle braking of about, in thisinstance, 60% of maximum available braking force.

When the driver wishes the vehicle to move the driver presses down withhis or her foot 14 on accelerator pedal 11 (refer FIG. 1) so as to,initially, move accelerator pedal from first position 15 through to idleposition 11 over, in this instance, a travel distance D of far end 47 ofpedal 11 of about 20 mm which results in a corresponding movement ofthrottle wire 19 sufficient to cause vented vacuum valve 21 to adjustthe amount of manifold pressure communicated to vacuum cylinder 24which, in turn, moves brake pedal arm 25 to a position which correspondsapproximately 10% of maximum available vehicle braking force.

As the driver presses down further on accelerator pedal 11 the pedalmoves past idle position 17 and in the direction of second position 16at which time (refer FIG. 3) brake pedal arm 25 is allowed to move toits rest position whereby minimal braking force is being exerted on thevehicle and, instead, positive acceleration commences by actuation ofthrottle wire 19 on carburetor 18 and as illustrated graphically in FIG.2B.

When the driver wishes the vehicle to decelerate the driver slowly liftshis or her foot 14 from accelerator pedal 11 which results in a reverseprogression of events to that described immediately above whereinpositive acceleration ceases as accelerator pedal 11 moves through toits idle position 17 and, at idle position 17 positive braking ofapproximately 10% in this instance is applied to the vehicle increasingto 60% as the accelerator pedal 11 is allowed to move to its rest orfirst position 15.

In most circumstances it would be expected that as accelerator pedal 11moves from its idle position 17 through to first position 15 the driverwill, at the same time, be moving his or her foot 14 from theaccelerator pedal 11 over to the vehicle brake pedal 23 thereby tocontinue to operate brake pedal 23 in the normal manner.

However, with the accelerator pedal unit 10 of the first embodimentinstalled there may be circumstances where the driver can rely on thebehaviour of the accelerator pedal 11 for acceleration and positionbraking in many driving situations.

When the engina is switched off solenoid valve 28 deactivates thesystem.

Similarly, in this instance, if cruise control or other automatedcontrol system of the vehicle is enabled then such control system canswitch off solenoid valve 28 thereby deactivating the brake vacuum valvecontroller 20 and hence the accelerator pedal unit 10.

It will be observed that the arrangement according to the firstembodiment allows brake pedal 23 to be utilized as normal and tooverride the operation of the accelerator pedal unit 10.

Furthermore, because brake pedal 23 is caused to move when acceleratorpedal 11 activates the braking function it follows that the brake lightsof the vehicle will be activated as is usual when the brake pedal isdepressed on a normal vehicle. Thus, with this embodiment, drivers invehicles following a vehicle modified according to the first embodimentof the present invention will not be caught by surprise.

An advantage of the mechanical implementation of the first embodiment isthat it allows retention of feel over the controls and particularly thebraking control.

The mechanical implementation of the first embodiment is simple andcheap to implement. The arrangement generally provides for braking totake effect more quickly than would otherwise be the case and hence itis to be expected that, in many instances, braking distance of a vehiclemodified according to the first embodiment will be shortened as comparedwith a vehicle not so modified.

In the first embodiment as described with reference to FIG. 4 it is tobe noted that the existing throttle wire 19 is utilised. This ispossible in vehicles which have a throttle wire slack adjustmentmechanism in the carburetor or equivalent. In an alternative version aseparate wire can be used to sense position of the accelerator pedal 11.

Second Embodiment

With particular reference to FIG. 5 modifications to the generalbehaviour of the braking system are possible in accordance with furtherembodiments of the present invention.

In particular it is possible to incorporate a neutral zone 40 interposedbetween acceleration zone 41 and braking zone 42 whereby, over apredetermined angular movement Y° there is neither an accelerationapplied to the vehicle nor a braking effect applied to the vehicle.

With reference to FIG. 4 appropriate adjustment of the linkage ofthrottle wire 19 and adjustment of the linkage of brake wire 27 canprovide this neutral zone. In a particular preferred form the neutralzone extends to approximately 5° of angular movement of the acceleratorpedal which is to say Y=5°.

In a further particular form a mechanical detent 44 as seen in the insetof FIG. 5 can be linked in to the axis of rotation of the acceleratorpedal whereby the driver feels mechanical resistance at the angularposition of the accelerator pedal corresponding to neutral zone 40brought about by the alignments of mechanical detent 45 within cam 46.

Override System

In some situations it may be appropriate for the above described systemof both the first and second embodiments to be able to be overridden atthe command of the driver.

In one form an override system can be implemented by inserting solenoid43 is incorporated in the linkage of throttle wire 19 between carburetor18 and accelerator pedal 11 as shown in FIG. 4. The optional solenoid 43in one condition (for example energized) permits the 20 mm of play inthe throttle wire movement previously referred to in the 0description ofthe first embodiment. In a second (non-energised) position the solenoidtakes up the 20 mm of play thereby returning the behaviourcharacteristic of the accelerator pedal to that illustrated in FIG. 2A.This arrangement also provides a “fail safe” system whereby, should thesolenoid lose power, the operation of the vehicle automatically becomeswhat might currently be termed “conventional” in accordance with theprior art diagram of FIG. 2A.

In a preferred system solenoids 28 and 43 are wired in series so thatthey are both energized and de-energised together.

The solenoid 43 can also be operated by other electronic systems withinthe vehicle. For example, if cruise control is enabled the solenoid maybe caused to operate SO as to return the system to the operation of FIG.2A.

In a further modification the solenoid can be arranged to exert itsoperation in a cushioned or controlled way, for example when cruisecontrol is caused to cut out when the brake pedal is operated. In thissituation it would be preferable if the characteristic reflected in FIG.2B or FIG. 5 came into operation gradually rather than with immediateeffect. This can be given effect by, for example, including a pneumaticresistance arrangement whereby the solenoid 43 can move to the off(de-energised) condition immediately but moving from the de-energised tothe energized position will be forced to work against a pneumatic bleedarrangement which causes the solenoid ram to move at a controlled,predetermined rate to the activated position.

The above describes only some embodiments of the present invention andmodifications, obvious to those skilled in the art, can be made theretowithout departing from the scope and spirit of the present invention.

For example, instead of wire systems being used for throttle wire 19and/or brake wire 27 alternative systems including cylinder and pistonsystems can be used.

Also the arrangement of the brake vacuum valve controller 20 of thefirst embodiment as illustrated particularly in FIG. 4 is particularlysuited for retrofitting as a kit to vehicles after their manufacture.

The behaviour illustrated in FIG. 2B may also be achieved in other ways,for example with electronic control systems, particularly where suchsystems are designed into a vehicle and provided with the vehicle duringits manufacture.

In the specific instance of FIG. 1 the travel distance of far end 47 ofaccelerator pedal 11 has been described for a distance D equal to 20mms. In an alternative form the distance D can be increased up to 35 mm.This will be dependent upon the particular type and size of the vehiclein which the system of the present invention is installed. For mostsituations it would be expected that D will lie in the range 10–40 mmand, more preferably, in the range 20–35 mm.

INDUSTRIAL APPLICABILITY

The above described arrangement is particularly suited for use to modifythe behaviour of accelerator pedals in passenger motor vehicles forwhich the primary motive source is an internal combustion engine.However the principals and behaviour of operation of the acceleratorpedal in accordance with embodiments of the present invention may alsobe applied to other forms of vehicle and also other forms of vehiclewherein the primary motive source may be other than an internalcombustion engine, for example a combined combustion engine and electricdrive.

1. An accelerator pedal unit for a vehicle said vehicle having a singleseparate brake pedal and a single separate accelerator pedal, theaccelerator pedal unit comprising: a throttle wire connecting saidsingle separate accelerator pedal to an engine of the vehicle and saidseparate brake pedal of said vehicle being connected to brakes of thevehicle; said accelerator pedal arranged to operate over a predeterminedpedal travel which spans from a first position to an idle positionthrough to a second position; and said accelerator pedal unit furthercomprising a brake wire connected to said separate brake pedal andconnecting said accelerator pedal to said brakes of the vehicle; wherebysaid engine is caused to progressively increase the magnitude of urgingforce applied to said vehicle as said accelerator pedal moves from saididle position to said second position; and whereby said vehicle via saidbrakes is caused to progressively increase magnitude of braking forceapplied to said vehicle with corresponding induced movement of theseparate brake pedal as said accelerator pedal and said throttle wiremove correspondingly from said idle position to said first position;said accelerator pedal biased in use towards said first position whereinsaid connections of said throttle wire and said brake wire are such thatsaid brake wire moves as said throttle wire moves between said firstposition of said single separate accelerator pedal and said idleposition.
 2. The accelerator pedal unit of claim 1 wherein when saidaccelerator pedal is at said idle position said urging force isapproximately 0 and said braking force is approximately 10% of a maximumbraking force.
 3. The accelerator pedal unit of claim 1 wherein brakelights of said vehicle are operated when said brakes are actuated. 4.The accelerator pedal unit of claim 1 wherein, when said acceleratorpedal is at said idle position, said positive urging force isapproximately zero and said braking force is approximately zero percentof maximum braking force.
 5. The accelerator pedal unit of claim 1wherein said accelerator pedal maintains said idle position over apredetermined angular range of movement.
 6. The accelerator pedal unitof claim 5 wherein said predetermined angular range of movement isapproximately 5°.
 7. The accelerator pedal unit of claim 1, comprising avacuum cylinder engaged with the accelerator pedal and throttle wire andthe separate brake pedal and brake wire such that operating theaccelerator pedal between the idle and first positions induces thevacuum cylinder to apply a corresponding force to the brake wire to movethe separate brake pedal to the position corresponding to the appliedbraking force.
 8. The accelerator pedal of claim 1, wherein the singleseparate accelerator pedal is pivotable about a single pivot axis so asto be movable between the first position to the idle position andthrough to the second position.